1. Field of theTechnology
The present technology relates to a video game device and an image processing program, and more particularly to a video game device and an image processing program capable of solving the problem that a player character controlled by a player is hidden behind a building, which may occur when an image of a building, for example, is rendered in a 3D virtual game space together with an image of the player character.
2. Description of the Background Art
In a video game where a player controls a player character in a 3D virtual game space, the player character may be hidden behind a building in the game screen when the player character moves between buildings. In such a case, it is typical in the prior art that the player's viewpoint is shifted so that the player character can be seen. Depending on the type of the video game, it may be preferred that the game image is displayed such that the virtual game space is always viewed from the same direction without shifting the viewpoint.
Japanese Patent No. 2902352 discloses a technique in which a transparency operation is performed on a wall or a floor only when they are overlapping with, or close to, the display position of the player character so that the player character can always be seen on the display screen.
Japanese Patent No. 3141737 discloses a technique in which it is determined whether or not an obstacle is hiding a subject, and a transparency operation is performed on the obstacle only when the obstacle is hiding the subject so that the player character can always be seen on the display screen.
With the technique of Japanese Patent No. 2902352, when the player character is hidden behind a wall of a building, the wall is entirely made transparent, thereby significantly altering the atmosphere of the game field. Similarly with the technique of Japanese Patent No. 3141737, when the subject is hidden behind an obstacle, the obstacle is entirely made transparent, thereby significantly altering the atmosphere of the game field due to the abrupt disappearance of the obstacle. With either technique, each object needs to be rendered after determining whether or not it is hiding the player character (or the subject) based on the positional relationship between the object, the player character (or the subject) and the viewpoint, for each of a plurality of objects such as a wall or an obstacle. Therefore, the processing load for the determination process increases as the number of objects increases.